The dissociation between data management and data ownership makes it difficult to protect data security and privacy in cloud storage systems.Traditional encryption technologies are not suitable for data protection in ...The dissociation between data management and data ownership makes it difficult to protect data security and privacy in cloud storage systems.Traditional encryption technologies are not suitable for data protection in cloud storage systems.A novel multi-authority proxy re-encryption mechanism based on ciphertext-policy attribute-based encryption（MPRE-CPABE） is proposed for cloud storage systems.MPRE-CPABE requires data owner to split each file into two blocks,one big block and one small block.The small block is used to encrypt the big one as the private key,and then the encrypted big block will be uploaded to the cloud storage system.Even if the uploaded big block of file is stolen,illegal users cannot get the complete information of the file easily.Ciphertext-policy attribute-based encryption（CPABE）is always criticized for its heavy overload and insecure issues when distributing keys or revoking user＇s access right.MPRE-CPABE applies CPABE to the multi-authority cloud storage system,and solves the above issues.The weighted access structure（WAS） is proposed to support a variety of fine-grained threshold access control policy in multi-authority environments,and reduce the computational cost of key distribution.Meanwhile,MPRE-CPABE uses proxy re-encryption to reduce the computational cost of access revocation.Experiments are implemented on platforms of Ubuntu and CloudSim.Experimental results show that MPRE-CPABE can greatly reduce the computational cost of the generation of key components and the revocation of user＇s access right.MPRE-CPABE is also proved secure under the security model of decisional bilinear Diffie-Hellman（DBDH）.展开更多
Distributed information systems require complex access control which depends upon attributes of protected data and access policies.Traditionally,to enforce the access control,a file server is used to store all data an...Distributed information systems require complex access control which depends upon attributes of protected data and access policies.Traditionally,to enforce the access control,a file server is used to store all data and act as a reference to check the user.Apparently,the drawback of this system is that the security is based on the file server and the data are stored in plaintext.Attribute-based encryption(ABE) is introduced first by Sahai and Waters and can enable an access control mechanism over encrypted data by specifying the users’ attributes. According to this mechanism,even though the file server is compromised,we can still keep the security of the data. Besides the access control,user may be deprived of the ability in some situation,for example paying TV.More previous ABE constructions are proven secure in the selective model of security that attacker must announce the target he intends to attack before seeing the public parameters.And few of previous ABE constructions realize revocation of the users’ key.This paper presents an ABE scheme that supports revocation and has full security in adaptive model.We adapt the dual system encryption technique recently introduced by Waters to ABE to realize full security.展开更多
Attribute-Based Encryption (ABE) has been widely used for ciphertext retrieval in the cloud environment.However,bi-flexible attribute control and privacy keywords are difficult problems that have yet to be solved.In t...Attribute-Based Encryption (ABE) has been widely used for ciphertext retrieval in the cloud environment.However,bi-flexible attribute control and privacy keywords are difficult problems that have yet to be solved.In this paper,we introduce the denial of access policy and the mutual matching algorithm of a dataset used to realize bidirectional control of attributes in the cloud server.To solve the problem of keyword privacy,we construct a security trapdoor by adding random numbers that effectively resist keyword guessing attacks from cloud servers and external attackers.System security is reduced to the Deterministic Bilinear Diffie-Hellman (DBDH) hypothesis problem.We validate our scheme through theoretical security analysis and experimental verification.Experiments are conducted on a real dataset,and results show that the scheme has higher security and retrieval efficiency than previous methods.展开更多
基金supported by the National Natural Science Foundation of China(6120200461472192)+1 种基金the Special Fund for Fast Sharing of Science Paper in Net Era by CSTD(2013116)the Natural Science Fund of Higher Education of Jiangsu Province(14KJB520014)
文摘The dissociation between data management and data ownership makes it difficult to protect data security and privacy in cloud storage systems.Traditional encryption technologies are not suitable for data protection in cloud storage systems.A novel multi-authority proxy re-encryption mechanism based on ciphertext-policy attribute-based encryption（MPRE-CPABE） is proposed for cloud storage systems.MPRE-CPABE requires data owner to split each file into two blocks,one big block and one small block.The small block is used to encrypt the big one as the private key,and then the encrypted big block will be uploaded to the cloud storage system.Even if the uploaded big block of file is stolen,illegal users cannot get the complete information of the file easily.Ciphertext-policy attribute-based encryption（CPABE）is always criticized for its heavy overload and insecure issues when distributing keys or revoking user＇s access right.MPRE-CPABE applies CPABE to the multi-authority cloud storage system,and solves the above issues.The weighted access structure（WAS） is proposed to support a variety of fine-grained threshold access control policy in multi-authority environments,and reduce the computational cost of key distribution.Meanwhile,MPRE-CPABE uses proxy re-encryption to reduce the computational cost of access revocation.Experiments are implemented on platforms of Ubuntu and CloudSim.Experimental results show that MPRE-CPABE can greatly reduce the computational cost of the generation of key components and the revocation of user＇s access right.MPRE-CPABE is also proved secure under the security model of decisional bilinear Diffie-Hellman（DBDH）.
基金the National Natural Science Foundation of China(No.60972034)
文摘Distributed information systems require complex access control which depends upon attributes of protected data and access policies.Traditionally,to enforce the access control,a file server is used to store all data and act as a reference to check the user.Apparently,the drawback of this system is that the security is based on the file server and the data are stored in plaintext.Attribute-based encryption(ABE) is introduced first by Sahai and Waters and can enable an access control mechanism over encrypted data by specifying the users’ attributes. According to this mechanism,even though the file server is compromised,we can still keep the security of the data. Besides the access control,user may be deprived of the ability in some situation,for example paying TV.More previous ABE constructions are proven secure in the selective model of security that attacker must announce the target he intends to attack before seeing the public parameters.And few of previous ABE constructions realize revocation of the users’ key.This paper presents an ABE scheme that supports revocation and has full security in adaptive model.We adapt the dual system encryption technique recently introduced by Waters to ABE to realize full security.
文摘Attribute-Based Encryption (ABE) has been widely used for ciphertext retrieval in the cloud environment.However,bi-flexible attribute control and privacy keywords are difficult problems that have yet to be solved.In this paper,we introduce the denial of access policy and the mutual matching algorithm of a dataset used to realize bidirectional control of attributes in the cloud server.To solve the problem of keyword privacy,we construct a security trapdoor by adding random numbers that effectively resist keyword guessing attacks from cloud servers and external attackers.System security is reduced to the Deterministic Bilinear Diffie-Hellman (DBDH) hypothesis problem.We validate our scheme through theoretical security analysis and experimental verification.Experiments are conducted on a real dataset,and results show that the scheme has higher security and retrieval efficiency than previous methods.
